Color Selection Aid For Target Objects Such As Dental Objects

ABSTRACT

The base body (12) extends in two dimensions between the inner walls and the outer walls, with color selection areas (30) and reference features (32) arranged on the auxiliary color selection body. The auxiliary color selection body can be arranged in the vicinity of a target object (34) such that a straight line passing through two target object proximity points (38, 40, 42) on the inner walls sweeps across the target object.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Patent Application No. 18190558.9 filed on Aug. 23, 2018, the disclosure of which is incorporated herein by reference in its entirety. This application also claims priority to European Patent Application No. 18190543.1 filed on Aug. 23, 2018, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The invention relates to an auxiliary color selection body.

BACKGROUND OF THE INVENTION

Shade guides have been known for a long time, for example from DE 195 09 830 A1 and corresponding U.S. Pat. No. 5,653,589, which is hereby incorporated by reference in its entirety. Such a shade guide serves to ensure the best possible color selection of a replacement tooth for the patient.

Such a replacement tooth, for example, is surrounded by two healthy teeth or has a healthy neighboring tooth. The aim is to adapt the color of the denture to the surroundings so that the dental restoration is as inconspicuous as possible.

In the practice, the shade guide is held close to the healthy teeth, using different color selection areas on a trial basis, until the color selection area which is closest to the color and shade of a neighboring tooth is determined.

A problem with this resides in the fact that teeth typically show a color gradient. The similarity is evaluated differently, depending onto which place the dentist holds the tooth shade guide including the respective shade selection field.

In this respect, improvement is made concerning the solution according to EP 2 255 749 A1 and corresponding US 2010304323, which is hereby incorporated by reference in its entirety. With this solution, the color selection areas are significantly smaller than with conventional tooth guides, so that each color selection area only comprises a fraction of the dimensions of a tooth. Further dental color key and dental shade technology is set forth in U.S. Pat. No. 9,931,188, U.S. Pat. No. 4,541,801, U.S. Pat. No. 5,177,694, U.S. Pat. No. 6,007,332, U.S. Pat. No. 6,755,646, U.S. Pat. No. 7,006,126, US 20030235799, US 20040252303, and US 20090246727, which are all hereby incorporated by reference in their entirety. Further methods and systems used in the dental field include US 20060177792, US 10,076,388, U.S. Pat. No. 6,345,984, U.S. Pat. No. 9,775,491 B2, US 2011212420, US 20130060532, US 2013158958, US 20170319293 and U.S. Pat. No. 7,717,708, which are hereby incorporated by reference in their entirety.

This solution of a very small color key has the advantage that several color selection areas can be held next to the healthy tooth for the purposes of comparison in order to be able to perform better shade comparison.

Such small color selection areas, on the one hand, are hardly visible and on the other hand are more susceptible to soiling.

For example, if saliva gets in contact with the shade guide, that part of the shade guide will reflect stronger, giving a significantly different optical impression.

Experiments with different test persons using the known shade guides including color selection aids, revealed that the test persons assume color match and color similarity being very different if they use the known shade guides in the conventional way.

SUMMARY OF THE INVENTION

In contrast, the invention is to provide an auxiliary color selection body, which is improved in terms of assessment consistency of a color comparison result.

This problem is solved by the claims. Advantageous embodiments result from the subclaims.

According to the invention, it is intended to provide the base body of the auxiliary color selection body of the invention with at least two inner walls, which, in any case in the extension, do not extend towards each other, but at an angle. This angle can be obtuse or acute, but may also rectangular or 90 degrees.

On the other opposite side of the base body, two outer walls preferably extend crosswise to each other, rather one behind the other.

In this respect, the base body forms a two-dimensional or three-dimensional element with an elongated and bent course. Instead of the bend, an arc can also be realized so that the transition between the two inner walls is rounded.

The elongated element, i.e. the base body, has color selection areas and reference features. They are appropriately arranged, preferably such that the color selection areas are closer to the inner walls than the reference features.

The color selection areas include color shades used in the dental field, which match the colors and shades of patients' natural teeth. Such colors are provided by shade guide systems in the dental field by which dental materials are matched to provide the dental restoration that matches the patient's tooth color as close as possible. Many dental materials are based off the Vita Shade Guide color system which includes up to 16 or 17 or more shades and bleach shades as well.

Color perception is more accurate and has fewer metamerism effects when color corrected lighting is used to evaluate the three components: hue, chroma, and value. Hue is a family or group of wavelengths that have a similar appearance. Chroma is the level of saturation of any particular hue. The value is the level of whiteness or darkness.

Shade perception and color determination is a field of study defined by mathematics. Color interpretation is often defined scientifically in a mathematical 3-D format. The format can be plotted as seen in Munsell's color sphere.

Each color is a point in space represented by three components on X, Y, and Z planes and given the identification of L*a*b*, which has been defined by the International Lighting Commission (Commission Internationale de l′Eclairage; CIE). The distance between any two colors in 3-D space is defined as Delta E. When the difference in Delta E is large enough, the eyes can perceive a difference.

According to the invention, provision is now made to place the auxiliary color selection body with the base body to be close to a target object such that both the first and second inner walls are adjacent to the target object. The neighboring relation results in that a target object proximity point to be generated on each inner wall. A straight line that would extend or be placed between these two proximity points sweeps across the target object.

This results in both inner walls and the color selection areas adjacent to the inner walls to be arranged close to the target object, and subsequently, also the aforementioned bend or arc between the inner walls becomes close to the target object.

It is preferred that the target objects are dental objects, such as neighboring teeth of dental restorations to be created. The color selection areas are then as close as possible to the neighboring tooth which is to be evaluated. In particular, they surround it from at least two sides. According to the invention, it is advantageous for exactly one tooth to be used as the base for the comparison result. This is also realized by the bent and preferably essentially U-shaped course of the base body of the invention. The base body, in a double function, then also covers the interfering and non-interesting areas outside the reference tooth.

Surprisingly, this approach results in a significantly improved comparison result, as experiments on the test subjects have revealed.

The solution of the invention can also be defined using another model. First, a circle is defined outside of which the base body extends. The inner circle is intended to hold at least a large part of the target object, for example a tooth. The inner circle contacts the base body at two or three inner walls at points that are clearly spaced apart. The distance can be defined by an inner circle angle of at least 70 degrees of the two points of contact.

This ensures that the inner walls of the base body extend at least partially obliquely to each other. Also, realization of round inner walls, which partly abut the inner circle, is not excluded with this model. Outside the inner circle, the base body including color selection areas extend, which color selection areas in turn are quite close to the inner circle.

The proximity is defined by a central circle, the radius of which is greater than the radius of the inner circle, wherein both circles extend concentrically to each other.

The color selection areas extend in the space between the inner circle and the center circle.

Outside the central circle, a concentric outer circle is defined, where the base body and the reference features extend.

In an advantageous embodiment, the reference features extend between the center circle and the outer circle.

The outer circle has a radius of less than 25 mm and preferably a diameter of about 20 mm.

This approach also has the surprising advantage that the arrangement of the color selection areas at least partially surrounding the target object, and simultaneously the close proximity between the target object and the color selection areas as well as coverage of non-interesting areas by the base body results in an improved comparison result.

According to the invention, it is advantageous for the reference features, such as reference surfaces, to be located closer to the outside of the base body. Such reference features can be used for colorimetric referencing, but also for visual referencing, but also for geometric referencing.

In an advantageous embodiment of the invention, coding parameters are attached to the auxiliary color selection body. They can consist of a plurality of coding areas, but only one coding area is also possible. There are no limitations on the nature of the code. As an example, the QR code shall herein be mentioned. QR code (abbreviated from Quick Response Code) is a type of matrix barcode (or two-dimensional barcode). A barcode is a machine-readable optical label that contains information about the item to which it is attached. In practice, QR codes often contain data for a locator, identifier, or tracker that points to a website or application. A QR code uses four standardized encoding modes (numeric, alphanumeric, byte/binary, and kanji) to store data efficiently; extensions may also be used. The coding parameters may include, but are not limited to, parameters based on the user's needs.

The target object can be a dental restoration, a natural tooth, but also, for example, a tooth stump or the gingiva. Human teeth can range in length and/or width from 2 or 3 mm to 12 mm, depending on which tooth is at issue. Ranges of lengths and widths may vary depending on age, gender, size and can include 5.5-10 mm, 7-11 mm, 4-8 mm, 6.5-9 mm, and 4-12 mm. Lengths may also be as great as 16-18 mm. Accordingly, the target area will be a size in which a natural human tooth can fit and possibly tissue surrounding the natural human teeth such as gingival tissue.

The inner contour and inner walls of the auxiliary color selection body can be curved to match the tooth outer contour.

The base body can be U-shaped, L-shaped or ring-shaped and the inner flanks or walls can be the inner walls of the U, L or ring.

The U-shaped and L-shaped design is particularly favourable. In this design, the base body is not ring-shaped but open.

This results in the target object being visible in the central center area adjacent to the color selection areas, and additionally in the open area of the base body.

The open area of the base body does not cover the target object, so that it remains freely visible and can be easily captured by a camera, for example.

A larger part of the tooth, and if necessary also the gums, is visible and available for comparison purposes.

It is also particularly advantageous that the base body and thus the color selection areas and reference characteristics are on the same plane as the target object, i.e. can be brought to the same height.

An anterior tooth is labially curved. The recess, i.e. the central area of the base body, surrounds the recess, preferably partially, and the arching of the tooth protrudes into it.

This makes it possible to keep the tooth and the base body on exactly the same level.

This is particularly advantageous because the scan results are not distorted by shadows or focus problems.

According to the invention, the capture can be automated without the need for error-prone user intervention.

In the advantageous embodiment of the auxiliary color selection body of the invention, it is intended that two color selection areas having the same brightness and color are opposite to each other in relation to the target object, and preferably are located diametrically to each other.

This may also be true with color selection areas having a color distance Delta E<0.6.

It is preferred that reference features having planar shape are attached to the color selection auxiliary body, which are spaced apart from each another, especially diametrically opposed to each another, which reference feature surfaces have clear geometric assignment to the inner walls, especially two reference features having the same distance to the respective adjacent inner walls.

The color selection areas can have tooth colors, residual limb colors and/or gingiva colors.

It is advantageous for the base body to essentially be horseshoe-shaped on the outside and the reference features to be maximally spaced apart from the inner walls on the outer walls of the side legs of the horseshoe.

The outer legs may also be more spaced than the center leg to accommodate the reference features.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, details and features will arise from the following description of several examples of the invention while making reference to the drawing, wherein:

FIG. 1, in an embodiment, is a view of an auxiliary color selection body according to the invention;

FIG. 2 is a schematic view of an auxiliary color selection body according to the invention;

FIG. 3 is another embodiment of an auxiliary color selection body according to the invention in schematic perspective view; and

FIG. 4 is another embodiment of a system according to the invention consisting of a camera device and an auxiliary color selection body according to the invention.

DETAILED DESCRIPTION

FIG. 1 shows an auxiliary color selection body 10 having a U-shape or a horseshoe shape. As can be seen, the actual structure differs from both the U-shape and the horseshoe-shape and also includes as the shapes those depicted herein.

The auxiliary color selection body 10 comprises a base body 12. The base body 12 is preferably made of a solid material such as plastic, ceramic, metal or a composite thereof. Part of the color selection body 10, on the other hand, is designed as a disposable part that can be removed from the base body. Any and all parts of the auxiliary color section body 10 may be made to be disposable or reusable.

In the present case, a label 14 is affixed to the base body 12 comprising various elements described below.

The base body 12 is shape-determining in that the shape of the base body according to the invention and thus of the auxiliary color selection body 10 substantially contributes to the function according to the invention.

The base body 12 has two inner walls 16 and 18, which extend transversely to each other. In the example shown, a third inner wall 20 is provided, which in turn extends transversely to the inner wall 18. Herein, solely for the sake of exemplification, the inner walls 16 and 20 extend at right angles to the inner wall 18.

The base body 12 is limited to the outside by outer walls 22, 24, 26. The operationally relevant parts of the auxiliary color selection body 10 extend between the inner walls 16, 18 and 20 and the outer walls 22, 24 and 26. They include color selection areas 30 and reference features 32. The color selection areas 30 extend close to a target object 34. The target object 34 is adjacent to the inner walls 16, 18 and 20 and in the example shown is arranged in the space spanned by said walls. The color selection areas may comprise as many colors/shades as desired, any number such as but not limited to, from 2 or 3 to 10, 15, 20, 25, 30, 35, 40 45, or 50 depending on how many different colors there may be to choose from.

Each inner wall has at least one proximity point, at which it is situated adjacent to and close to the target object 34. Herein, the points of proximity 38 and 40 are mentioned. For the inner wall 20, reference may be made to the proximity point 42.

A straight line 44 running through two of these points, i.e. 38 and 40, 40 and 42, or 38 and 42, crosses the target object 34.

In other words, the target object 34 is closely adjacent to the inner walls 16, 18, 20, which extend diagonally or transversely to each other, and is at least partially located in the space or area spanned by them.

Outside the color selection areas 30, the reference features 32 are attached to the auxiliary color selection body 10. Thus, they are adjacent to the outer walls 22, 24, 26.

The reference features 32 may be applied either on the base body 12 or on the label 14.

In a further elaboration, reference features 32 are affixed both on the base body 12 and on the label 14.

The auxiliary color selection body 10 also comprises coding parameters with coding areas 50. They extend in the area of a center leg 52 of the base body 12. They are adjacent to the outer wall 24.

In the example shown, the center leg 52 is slightly wider than the side legs 54, which extend away from it.

The bottom part of the center leg 52 also serves as a gripping handle 55 for gripping and positioning the auxiliary color selection body 10 of the present invention.

FIG. 2 shows a schematic representation of another version of an auxiliary color selection body 10 according to the invention. An inner wall 20 and an inner wall 18 of the base body 12 are shown herein, with the inner walls 18 and 20 contacting each other at a point in the region of a corner 60.

The base body 10 extends outside an inner circle 62. The inner circle 62 contacts the inner walls 18 and 20 at two points 40 and 42 which extend at an angle of 90° to each other relative to the inner circle 62.

Adjacent to the inner circle 62 the color selection areas 30 are located. They are arranged within a center circle 64.

Even further outside, i.e. within an outer circle 66, the reference features 32 not shown in FIG. 2 are arranged. At the same time, the base body 12 as a whole extends within the outer circle 66.

FIG. 3 shows another embodiment of an auxiliary color selection body 10 according to the invention. A bite element 70 extends backwards from the base body 12. The bite element 70 is intended to be clamped between the jaws or dental arches of a patient in a manner known per se to enable fixed positioning in place, as desired by the dentist.

FIG. 4 shows a system 72 consisting of a camera device 74 and the auxiliary color selection body 10 of the invention. The camera device 74, for example, can be connected to a smartphone 75, which, in addition to a camera unit 76, also comprises a flash LED 78.

A spacer 80 is provided for fixed recording parameters. It consists of a short tube of fixed length, which can also be attached to the base body 12 or, if necessary, to the smartphone 75.

The spacer 80 consists of a light-proof material thus shielding extraneous light. This results in constant recording parameters regardless of the ambient light situation. In addition, the same focusing conditions are always achieved with the spacer 80. It has an inner diameter and thus an inner surface that is just large enough for the base body 12 to fit in. It is hollow and tubular, but can have any cross-section, thus also deviating from the circular shape.

Using the inventive camera device 74 and the corresponding image analysis, even better determination of a target tooth color based on the comparison result will be allowed.

As an auxiliary color selection body, it is or can be used in a system. In some embodiments, the present disclosure may be implemented using a system having a camera, a processor, an electronic data storage unit, and a display. The camera can be a standard camera, an infrared dot-projection detector, flood illuminator camera, structured-light three-dimensional scanner, standard infrared detector, ultrasonic imaging device, Doppler detector, or any other suitable visualization system capable of capturing information related to a patient's dentition. The processor can be a single processor having one or more cores, or a plurality of processors connected by a bus, network, or other data link. The electronic data storage unit can be any form of non-transitory computer-readable storage medium suitable for storing the data produced by the system. The display can be any display suitable for displaying a digital color or grayscale image.

In some embodiments, the camera, processor, electronic data storage unit, and digital display are components of a single device. The single device may be a smartphone, tablet, laptop computer, personal digital assistant, or other computing device.

In some embodiments, the processor is in communication over a network, which could be wired or wireless, with an external processor used for performing one or more calculation steps and/or a network-attached electronic data storage unit. In some embodiments, the present disclosure makes use of cloud computing to perform one or more calculations steps remotely and/or remote storage to enable the storage of data remotely for collaborative or remote analysis. In some embodiments, the system comprises a plurality of graphical user interfaces to permit multiple users to view or analyze the same data.

In some embodiments, the system operates to provide one or more users with a visualization of a virtual dental model of a patient's teeth, which may be altered to visualize the effect of one or more dental or orthodontic alterations. In some embodiments, this allows the one or more users to visualize a “before” dentition image, i.e., the appearance of a patient's dentition prior to a dental or orthodontic procedure, and an “after” dentition image, i.e., a representation of the expected appearance of a patient's dentition after a proposed dental or orthodontic procedure.

In some embodiments, the system operates by capturing information related to a patient's dentition using a camera, creating a model of the patient's dentition on a processor, fitting a model of a proposed post-alteration dentition to the patient's dentition on the processor, coloring the model of the proposed post-alteration dentition to match an expected real post-alteration coloration, and displaying the fitted model of the proposed post-alteration dentition in place of the patient's actual dentition on a display which otherwise shows the patient's actual facial features. The information related to a patient's dentition, the model of the patient's dentition, and the model of the proposed post-alteration dentition may be stored on an electronic data storage unit. In some embodiments, the operations are performed in real-time.

In some embodiments, a user interface is configured such that a user may view the “before” dentition image and the “after” dentition image simultaneously either side-by-side or with a full or partial overlay.

Where used herein, the term “non-transitory” is a limitation on the computer-readable storage medium itself—that is, it is tangible and not a signal—as opposed to a limitation on the persistence of data storage. A non-transitory computer-readable storage medium does not necessarily store information permanently. Random access memory (which may be volatile, non-volatile, dynamic, static, etc.), read-only memory, flash memory, memory caches, or any other tangible, computer-readable storage medium, whether synchronous or asynchronous, embodies it.

Although the invention is illustrated above, partly with reference to some preferred embodiments, it must be understood that numerous modifications and combinations of different features of the embodiments can be made. All of these modifications lie within the scope of the appended claims. 

1. An auxiliary color selection body for dental objects (34) comprising a base body (12) having at least two inner flanks or walls (16, 18, 20) which extend transversely with respect to each other and from which inner walls the base body extends outwards as far as to outer walls (22, 24, 26), and wherein the base body, as viewed two dimensionally, extends between the inner walls and the outer walls, having color selection areas (30) and reference features (32) which are arranged on the auxiliary color selection body (10), and wherein the auxiliary color selection body is configured for placement in a vicinity of a target object, such that a straight line (44) passing through two target object proximity points (38, 40, 42) on the inner walls sweeps across the target object (34).
 2. The auxiliary color selection body according to claim 1, wherein the at least two inner walls (16, 18, 20) extend at right angles to each other.
 3. An auxiliary color selection body for dental objects comprising a base body, wherein the base body extends outside an inner circle (62) having a radius of between 4 and 9 mm, which, at at least two points, contacts an inner contour of the base body having at least 2 inner walls (16, 18, 20), which, in relation to the center of the inner circle, extend at an angle of at least 70 degrees to each other and in which inner circle at least one region of a target object (34) is accommodated, so that color selection areas (30) on the base body (12) are formed within a center circle (64) concentric to the inner circle and having a radius of less than or equal to 25 mm, and wherein reference features (32) are formed on the base body within an outer circle (66) surrounding the base body and touching an outer contour thereof at at least one point, the outer circle being concentric to the inner circle and having a radius of less than or equal to 25 mm.
 4. The auxiliary color selection body according to claim 3, wherein the center circle (64) has a radius of less than or equal to 15 mm.
 5. The auxiliary color selection body according to claim 1, wherein the reference features comprise geometric indications to refer to a two-dimensional projection of three-dimensional structures, and wherein the walls (16, 18, 20, 22, 24, 26) are configured straight or curved as part of a contour of the base body.
 6. The auxiliary color selection body according to claim 1, wherein at least one part of the auxiliary color selection body (10) is designed as a disposable part, said disposable part comprising a part of the auxiliary color selection body being separable or removable from the base body (12), or the base body being configured as being a removable or a disposable part.
 7. The auxiliary color selection body according to claim 1, wherein at least two color selection areas (30) are arranged within a known color distance, and/or a brightness of which is equal, and are spaced apart from each other, adjacent to different walls (16, 18, 20) of the base body (12).
 8. The auxiliary color selection body according to claim 1, wherein up to 100% of the color selection areas (30) are attached adjacent to the inner walls (16, 18, 20) and/or an inner contour.
 9. The auxiliary color selection body according to claim 8, wherein 10% to 75%, of the color selection areas (30) are attached adjacent to the inner walls (16, 18, 20) and/or the inner contour.
 10. The auxiliary color selection body according to claim 1, wherein the color selection areas (30) have identical geometrical shapes with respect to each other and are designed as rectangles or squares adjoining each other, or are spaced apart by less than one third of their extent or size.
 11. The auxiliary color selection body according to claim 1, wherein the auxiliary color selection body (10) has coding parameters (50) for identifying and/or applying the color selection auxiliary body, the coding parameters (50) being less distant from the outer walls (22, 24, 26) of the auxiliary color selection body and of the base body (12) than from the inner walls (16, 18, 20) of the auxiliary color selection body and of the base body.
 12. The auxiliary color selection body according to claim 11, wherein the coding parameters (50) are in print or bar code.
 13. The auxiliary color selection body according to claim 1, wherein the color selection areas (30) and the coding parameters (50) are printed on a detachable label (14) which can be affixed to the base body (12), wherein the reference features (32) are attached to the base body outside the label (14) and are visible when the label is affixed.
 14. The auxiliary color selection body according to claim 1, wherein the number of color selection areas (30) is between 3 and 100, each color selection area being between 0.126 and 10 mm², wherein a width of the base body (12) is less than or equal to 40 mm and a height of the base body is than or equal to 30 mm.
 15. The auxiliary color selection body according to claim 1, wherein the color selection areas (30) comprise at least 3 different colors.
 16. The auxiliary color selection body according to claim 1, wherein a bite element (70) is provided which extends away from the base body (12), in a third dimension, as viewed in in a rear plan view.
 17. The auxiliary color selection body according to claim 16, wherein the bite element (70) is designed as a part separate from the base body (12), which separate part is disposable or reusable, or is integrally designed with the base body.
 18. The auxiliary color selection body according to claim 1, wherein the auxiliary color selection body is configured for use with and an upper or lower jaw.
 19. The auxiliary color selection body according to claim 1, wherein the base body (12) has at least one side leg, (54) having a length which is more than 5 millimeters and which length corresponds to a height of a human tooth and a width of which is at least 3 mm.
 20. The auxiliary color selection body according to claim 1, wherein the width is between 6 and 10 mm.
 21. The auxiliary color selection body according to claim 1, wherein the base body (12) has a central leg (52) with a gripping handle (55) which carries coding parameters (50) mounted on coding surfaces.
 22. A system comprising a camera device (74) and an auxiliary color selection body (10) according to claim 1, wherein the camera device (74) comprises a spacer (80), into the inner surface of which at least the base body (12) fits and which is light-impervious to exterior light.
 23. The auxiliary color selection body according to claim 1, wherein the base body is formed in one piece.
 24. The auxiliary color selection body according to claim 1, wherein the colour selection auxiliary body (10) is L-shaped or U-shaped.
 25. The auxiliary color selection body according to claim 1, wherein the color selection areas (30) and the reference features (32) on the color selection auxiliary body (10) are formed on the same plane as the target object (34). 